This invention relates, in general, to voltage level shifters and more particularly, to those voltage level shifters using complementary metal oxide semiconductor (CMOS) devices.
In many instances CMOS logic circuits operate from a power supply ranging from zero to plus five volts. However, when interfacing CMOS logic circuits with other circuits, such as industrial controls or display drivers, it is often desirable to have a larger voltage swing than from zero to plus five volts. Of course, generally speaking, the higher the voltage swing the more immune the circuit is to spurious noise transients. Such spurious noise transients are more likely to occur in an industrial environment. Accordingly, it will be appreciated that it would be desirable to have a circuit that can interface with a CMOS logic circuit and shift the output voltage swing of the CMOS circuit to one which is compatible with a circuit requiring a wider voltage swing or a different voltage level. It is desirable to have such an interface circuit that is small in size, fast in operating speed, and does not consume much power.
Accordingly, it is an object of the present invention to provide an improved CMOS level shifter circuit.
Yet another object of the present invention is to provide a level shifter circuit that has the advantages of speed, size, and low power consumption.